Evaporating apparatus.



P. KESTNBR.

EVAPORATING APPARATUS.

APPLIOATION FILED SEPT. 11, 1912 .1 60,607, Patented May 6, 1913.

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PAUL KESTNEB, OF LILLE, FREENCE, ASSIGNOR TO KES'INER EVAPORA TORCOMPANY,

F PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANI A.

nvarorme arrarus.

Specification of Letters Patent.

Patented May 6, 11%13.

Application filed September 11, 1912. Serial No. 719,810. I

provements in Evaporating Apparatus, of

which the following is a specification.

This invention relates to evaporating apparatus; and it comprises anevaporator opcrating in downward flow of the liquid to be concentratedand having a heating jacket surrounding the evaporating elements, aliquid distributing device near or at the top of the evaporator, aconduit for liquid communicating with said distributing device and aconnection between said heatingjacket and said conduit enablingutilization of fluid from said jacket in elevating liquid through saidconduit to said distributing device, and,

more specifically, a vertical tube evaporator having a plurality ofvertical tubes within a heating casing, a distributer for liquid at thetop of said tubes and a separator for llquid and vapor at the bottom ofsaid tubes, a feed conduit for the distributemand a pipe connectionbetween the heating jacket and the conduit for facilitating the passageof liquid upward through said conduit; all as more fully hereinafterdescribed and as claimed.

In the operation of vacuum pans and other evaporators where evaporationis performed in a downward passage of the liquid and where liquid is fedto the top of ,the apparatus, it is customary to supply, or help supply,the feed of the liquid by the aid of a pump. Heating is ordinarily doneby steam, live or exhaust as the case may be, or by vapor from apreceding efi'ect, fed into heating element. As heat is conveyed througha metal wall to the liquid to be evaporated, the heat and, consequently,the pressure are invariably greater in the heating element than in theevaporating element. The steam or'vapor, as the case may be, alwayscarries more or less air or other permanent gases which accumulate inthe heating element, not beingsubject to condensation in the heatingoperation; and it is customary to provide means for removing the gas.Ordinarily there is an air exit at a point remote fromthe point of entryof the steam or vapor, and through this exit, which is normally open,escape not only the air and other permanent no-condensable gases but acertain amount of steam or vapor mixed therewith, which are lost.Generally, but

not necessarily, in these downwardly operating evaporators, evaporationis performed within vertically placed tubes surrounded by and inclosedin a heating casing or jacket.

Occasionally, the heating fluid is conveyed through tubes or pipes,horizontally or vertically placed, over which the liquid trickles orpassesdownwardly. T have found that the gas in the heating elements,with or without a certain amount of the heating fluid itself, may beusefully employed in propelling, or facilitating the propulsion, of theliqui to the top of the evaporator. Where pans or evaporators are placedin multiple efiect, the difi'erence in pressure between succeedingefl'ects tends to cause a feed in the desired direction; and the same istrue of a single efl'ect working under vacuum or suction. But thisdifi'erence in pressure, or suction, -is often not suflicient to causeas rapid-and copious a feed as is desirable; and this is articularlytrue where the evaporator is o? comparatively great height; as in moderntypes of evaporators transmitting liquid as downwardly flowing filmsthrough'tfibes of comparatively great height. In the present inventionthis air or gas, together with more or less vapor is so utilized intransmitting liquid to the top of theevaporator. The air, or gas, orvapor so employed for propulsion may be directly sliifpplied; into thecurrent of liquid. As the e ect or evaporator is invariably workingunder less pressure than prevails in its heatlng elements, nocondensation of any of this steam or vapor can take place in theevaporator so supplied. The fluid, whether permanent %gas or steam orvapor, or a m1xture, w1ll go orward with the liquid to be evaporated andwill mingle with the vapors of heating element to assist in the flow ofliq uid. through a conduit to the top of the evaporating element is usedin an injectorlike device. lowest point in such conduit which conditionspermit. As stated, there is no reason why the fluid should not becontaeted with It should be supplied to the rality of comparatively longnarrow vertical tubes passing through a heating casing and provided witha common feed for all such tubes (or a group of tubes), and dischargingat their base into a particular separating point 6 for removal 0 chamberfor liquid and vapor, having means at the base for withdrawing liquid soseparated. u

In the accompanying illustration I have shown, more or lessdiagrammatically, certain embodiments of the described invention. Inthis showing, Figure 1 is a view,

partly in vertical section, of a single evaporator or effect, having theliquid'feed device described and of the type described; and Fig. 2 is asimilar view of a plurality of such effects (two are shown) 1n multiple-effect arrangement.

In the showing of Fig. 1, element 1 is a nest of comparatively narrowlong vertical tubes communicating at their top with distributing chamber2 and at their base with separating chamber 3 for liquid and vapor.

Outlet 4 provides for removal of separated vapor. The tubes aresurrounded by a casing' provided with inlet 5 for steam or heating vaporand havin an outlet 'at an upper gas, or gas and vapor.

Feed conduit 7 supplies liquid to the dis- 'tributing chamber. From theoutlet for gas and vapor, a pipe 8 leads to an injector-like device 9 inthe feed conduit. As shown in Fig. 1, this feed conduit may be su pliedin part by pipe 10 with liquid w ich has already passed throu h-' theapparatus.

Valve 11 'in the pipe om the as outlet allows control of t e removal 0gas and vapor and of the propulsion of liquid. Con- 'centratedliquid maybe removed from the i be used to prevent entrainment. In the.

system by valved plpe 12 and fresh liquid ma be introduced t roughvalved pipe 13. Va vs 14 permits control of the relat1ve roportion ofconcentrat'ed liquid returne to mingle; with fresh li' uid. With thisarra'ngement, whatever t e rate or manner of introduction of freshliquid and removal of' ished liquid fromithe evaporator, a sufiiclentamount of liquid can be. maintained in theevaporator at all times tokeep the evapcrating surfaces efiiciently covered. In llquid separatingchamber a depending baffie, 15, which may be spiral in section, may

structure ofFig. 2, two such effects, A and B, are combined'to form an aparatus operating 1n double-effect. In tEJS structure the twoevaporators are, or may be, exactly the same as the single effect ofFig. 1. As shown, like elements have like reference characters. There isa valved cross-over 16 which allows the thickened liquid from A to befed to B in any desired proportion.

In the operation of the structure of Fig. 1, fresh liquid is introducedthrough 13 while finished liquid is removed through 12. By suitablyopening valve 14, any desired proportion of once-treated liquid may, 1fdesired, be admixed with fresh inflowing liquid. By suitably openingvalve 11, air and, usually, some vapor from 6 pass into 9 giving upwhatever superheat they may have, and force the liquid upwardly through7 to distributer 2. This forcing may be done in part by the live forceof the air and vapor, and for this reason element 9 is advantageously aninjector but in large part it is also accomplished by the tendency ofthe air to rise in 7, taking up the liquid with it in the way familiarin alr-lift pumps. Ordinarily the effect is under the influence ofsuctionindueing means connected to 4 and the liquid tends to rise in 7for this reason while the injection of air and vapor from the heatercasing tends to lighten the liquid column and make the suctionmore'efi'ective. The air and vapor passing with the liquid into thedistributer join the vapor produced in the downward passage of theliquid through tubes 1. Arriving at the base of the tubes liquid passingto exit through 12. If valve 14 be closed, no finished liquid will jointhe fresh liquid; if it be partly opened any desired fraction of thethickened liquid may .be admixed with the fresh incoming liquid. 'If itbe used discontinuously, valve 14 may be opened and suflicient liquidallowed to enterthrough 13 to give the desired amountor volume in theapparatus. Then the feed may be discontinued or lessened. As the liq--uid diminishes in volume, more maybe allowed to enter through 13 fromtimeto time, or continuously; and after the concentration is complete,the apparatus may be discharged through 12.

The operation in the multiple effect of Fig. 2 may be much the same,except that finlshed liquid' is continuously sent in some proportionfrom A to B. By closing valves 14 in the appropriate connections of Aand B, the liquid may merely pass through the apparatus without a returnthrough the same eifect. Ordinarily in working in multiple effect, sincethe volume of liquid, with .than in first.

the same feed, is greater in the first efiect than in the second, and inthe second than in the third, etc., it is better to use the return feed(past 14:) more in the later effects If the valves 14 be kept closed and16 be kept'open, the apparatus of Fig. 2 operates in ordinary multipleeffect, without return of liquid through the same effect. Air or gasfrom another source maybe mingled with the liquid in conduit? to givethe air-lift effect but since the gas in the heating jacket must bedisposed of, it is better to use it. This enables the lifting effect tobe secured without cost and, in the case of high evaporators, permitsdispensing with a special liquid pump for each effect which must,ordinarily, otherwise be used. By using the return flow connection pastvalve 14 not only is an eflicient covering of the heating surfacespermitted, but the further advantage is secured that circulation throughthe apparatus may be made much more rapid than would correspond to asingle passage of liquid. Other things being equal, the more rapid theflow of a liquid over a heating surface, the more eficient is theabsorption of heat; and with the present device the flow may be made asrapid as may be desired without interference with the normal flow offresh liquid to and finished liquid from the apparatus.

What I claim is:-

1. In evaporating apparatus, heating and evaporating elements, a chamberat or near the top of the apparatus distributing liquid to saldevaporating elements, a chamber near the base of the apparatus forreceiving evaporated liquid, a conduit supplying liquid to thedistributing chamber and a pipe connection between the top of theheating element and a point in said conduit.

2. In evaporating apparatus, heating and evaporating elements, a chamberat or near the top of the apparatus distributing liquid to saidevaporating elements, a chamber near the base of the apparatus forreceiving evaporated liquid, a conduit supplying liquid to thedistributing chamber and a pipe connection between the top of theheating element and a point in said conduit, said point being providedwith an injector device into which said pipe connection enters.

3. In evaporating apparatus, heating and evaporating elements, a chamberat or near the top of the apparatus distributing liquid to saidevaporating elements, a chamber near the base of the apparatus forreceiving evaporated liquid, a conduit supplying liquid to thedistributing chamber, a pipe connection between the top of theheatingelement and a low point in said conduit and a pipe connection forevaporated liquid connecting said receiving chamber for evaporatedliquid and said conduit.

evaporating elements, a chamber at or near the top of the apparatusdistributing liquid to said evaporating elements, a chamber near thebase of the apparatus for receiving evaporated liquid, a conduitsupplying liquid to the distributing chamber, a pipe connection betweenthe top of the heatlng element and a point in said conduit, said pointbeing provided with an injector device into which said pipeconnectionenters, and a pipe connection for evaporated liquid connecting saidreceiving chamber for evaporated liquid and said conduit.

5. In an evaporating apparatus, a plurality of vertical evaporatingtubes,- a surrounding heating casing, a distributing chamber for liquidabove and supplying said tubes, a chamber at the base for evaporatedliquid, a conduit for incoming liquld supplying said distributingchamber and-a pipe connection between said heating casing and a point insaid conduit.

6. In an evaporating apparatus, a plurality of vertical evaporatingtubes, :1 surrounding heating casing, a distributing chamber for liquidabove and supplying said tubes, a chamber at the base for evaporatedliquid, a conduit for incoming liquid supplying said distributingchamber and a pipe connection between said heating casing and a point insaid'conduit, said point being provided with an injector device intowhich said pipe connection enters.

7. In an evaporating apparatus, a plurality of vertical evaporatlngtubes, a surrounding heating casing, a distributing chamber for liquidabove and supplying said tubes, a chamber at the base for evaporatingliquid, a conduit for incoming liquidsupplying said distributingchamber, a pipe. connection between said heating casing and a point insaid conduit, and a connection for evaporated liquid between saidreceiving chamber and said conduit.

8. In an evaporating apparatus, a plurality of vertical evaporatingtubes, a sur rounding heating casing, a distributing chamber for liquidabove and supplying said tubes, a chamber at the base for evaporatedliquid, a conduit for incoming liquid supplying said distributingchamber, a pipe connection between said heating casing and a point in'said conduit, said point being provided with an injector device intowhich said pipe connection enters, and a connection for evaporatedliquid between said receiving chamber and said conduit.

9. In an evaporator, a plurality of vertical evaporating tubes, aheating casing surrounding the same, a' distributer chamber for liquidabove and supplying the tubes, a

separating chamber of comparatively large volume at the base of thetubes, a conduit for liquld connected to said distributing chain-- her,a pipe connection between sa d heating jacket and said conduit, and apipe conthe apparatus preparatory 'to such down- 10 neetlon between thebase of said separating ward transit.

chamber and said conduit. In testimony whereof, I aflix my signature 10.In an; evaporating apparatus, means, in the presence of two subscribingwitnesses.

for evaporating liquid in downwiard transit, PAUL KESTNER heating meansfor thesame adapted to receive fluid under pressure and means oper.-Witnesses:

ated by fluid withdrawn from said heating J. LEBEY,

means for transmitting liquid to the top of A. W. KORBY.

